This invention relates generally to implants for repairing ducts and passageways in the body. More specifically, the invention relates to an apparatus and procedures for deploying a stent-graft in mammalian vasculature.
A variety of stent or stent-graft designs and deployment mechanisms have been developed. For various reasons, many of these stent-grafts tend to become displaced from the intended deployment site within a lumen upon deployment prior to being secured within the lumen. Thus, there is a need to improve stent or stent-graft deployment placement accuracy and reliability within a vessel. Additionally, there exists a need to improve upon the reliability of the devices used for deployment of the stent-grafts.
The present invention involves medical devices and method(s) for deploying an expandable stent or stent-graft within mammalian lumens. According to the present invention, a medical device comprises a stent (or stent-graft) which has a proximal portion and a distal portion, and means for progressively deploying or expanding the stent, preferably a tether or slip line, which is releaseably coupled to the stent. The line is arranged such that when it is released from the stent, the stent progressively expands in a direction from its proximal portion to its distal portion. In order to accomplish progressive expansion of the stent, according to one variation of the slip-line embodiment the line is preferably arranged in a sack knot configuration. According to a further aspect of the slip line embodiment, the line has a fixed end associated with the distal portion of the stent and a release end associated with the proximal portion of the stent. The release end of the line is pullable to actuate expansion of the stent.
The position of the line and the sack knot configuration can eliminate the need for doubling back the line to minimize the risk of snagging between the line and the stent device, thus, increasing deployment reliability. According to another aspect of the present invention, the stent or stent-graft described above may be placed within a lumen from a direction against the flow of fluid (e.g., blood). The stent expands or unfolds in a direction from its downstream end to its upstream end relative to the fluid flow. Thus, the present invention may minimize the likelihood of the device being displaced from the desired site before it is somewhat secured in the vessel during deployment.
According to another aspect of the invention, a delivery member, such as a catheter or guide wire, may be used to place the stent or stent-graft at the intended delivery site. When used with a catheter, the stent is releasably coupled, as described above, adjacent to the catheter""s shaft portion, with the stent""s proximal end being adjacent to the distal end of the catheter""s shaft portion.
A preferred method of the present invention involves placing a folded stent device attached to a stent delivery member, such as a catheter, at a desired site within a mammalian lumen, and then progressively unfolding the stent device in a direction away from the stent delivery member.